The use of polysaccharides and proteins in cosmetic compositions is well known in the art. Polysaccharides are known to be good humectanits, film formers, and function as skin moisturizers. Certain polysaccharides also have gelling ability and are useful in formation of higher viscosity liquid or solid, compositions. However, polysaccharides may tend to provide a heavy, sticky feel on the skin and, when used in quantities sufficient to cause gelling, may provide products which are not aesthetically pleasing. Proteins are naturally occuring long-chain, high molecular weight polymers formed by the self-condensation of amino acids. Proteins are excellent film formers, conditioning agents, and moisturizers for hair and skin. However, natural proteins generally have limited use in cosmetics and toiletries because they are somewhat unstable and tend to precipitate or denature when exposed to high temperatures or salt solutions. In addition they are easily hydrolyzed by chemical reagents or acids and bases. Even if these difficulties are overcome the formulation of cosmetic products containing proteins is further fraught with difficulty since each protein has an isoelectric point i.e. a pH at which the protein is neutral. If it is desired to form compositions having a pH which is below the isoelectric point of the protein, the protein may possibly form an insoluble precipitate if it is used in any appreciable amount.
Thus, there is a desire to formulate cosmetic compositions for application to skin or hair which provide the benefits of proteins (film forming, moisturization, and improving cosmetic appearance) and polysaccharides (humectant, film forming, and gelling ability), but without the drawbacks of each ingredient used separately.
It is an object of the invention to prepare a protein/polysaccharide complex ("PPC") which is the reaction product of at least one protein and at least one anionic polysaccharide, wherein the resulting PPC has a net charge which may be positive or negative, preferably negative.
It is an object of the invention to prepare a PPC which acts a gellant or viscosity modifier in aqueous based compositions.
It is an object of the invention to formulate a stable cosmetic compositions having a pH which is below the isoelectric point of the protein used to make the PPC.
It is an object of the invention to provide a method for forming a PPC having a net positive or negative charge (which makes the PPC water soluble).
It is an object of the invention to formulate cosmetic foundation makeup, and color cosmetic compositions which moisturize, color, and beautify the skin.
It is an object of the invention to formulate hair care products which cleanse, condition, and beautify hair.